Oligosaccharides occurring naturally in glycolipids, glycoproteins, or proteoglycans have many important biological functions. The carbohydrate portion (usually one or more oligosaccharides) of the molecule may have many roles, e.g. it serves as a recognition signal (it directs the glycoconjugate to a particular site, both in cells and multicellular organisms, at which the function of the glycoconjugate is executed), mediates adhesion of pathogenic bacteria to tissues (a necessary condition for an infectious process to take place), and mediates metastasis in neoplasia. New types of therapeutics and vaccines for inflammatory diseases (arthritis), bacterial infections, and cancer, based on oligosaccharides, are being developed. The utilization of oligosaccharides as disease-preventive agents is under active consideration. The need for various oligosaccharides has never been greater in biomedical sciences and industries. Unfortunately, it is not practical to obtain oligosaccharides from natural sources since they occur in very small quantities in complicated mixtures difficult to separate into individual components. Thus the efficient preparation of oligosaccharides, and their elaboration into glycopeptides and glycolipids, must be carried out by synthesis, organic chemical synthesis being the ultimate strategy. Oligosaccharides may be further elaborated into glycopeptides and glycolipids which have important utility on their own in the fields of medicine, biotechnology, food, and related technologies.